In the transition from classical to modern physics, the idea of taking some certain quantities as distinct or bounded values and keeping the rest continuous has proved useful in dealing with many problems. In this paper we assume an upper bound on the velocity of classical particles and indicate that applying this assumption to electromagnetism leads to a maximum strength for the magnetic field that shows acceptable agreement with the highest observed strengths in the cosmos, especially in magnetars. Despite its invalidity because of the complete ignoring of quantum physics, this approach can serve as an enjoyable and instructive exercise in introductory physics.